A number of machines involved in mining, construction and public works use rolls that are driven for the crushing, mining, milling and the like of earthen materials. These earth working rolls include an array of wear assemblies to engage the material to be worked. The assemblies generally include a component with an impact face that is releasably secured to a base attached to the roll. These components with the impact face are wear parts that are replaced after a certain length of use.
As one example, earth working tips can be provided in a roll crusher for the processing of earthen material in a mining operation. FIG. 1 shows a double roll crusher 10 including a pair of opposed rolls 12 to break up the mined material 14. Each roll 12 is fitted with an array of tips 20 configured to impact and separate the material. The tips are fixed to the roils 12. Generally, the rolls 12 are rotated in opposite directions so that the tips 20 are driven toward each other from the top during normal operation. However, the rolls may be operated in the opposite direction for clearing the crusher. Additionally the rolls may be designed so that the tips are driven toward each other at the bottom of the roll during normal operation. The broken material 14A passing through the roll crusher is deposited on a conveyor for transport to additional processing.
This kind of machinery is generally capital equipment and an important part of the processing operation. Minimizing downtime for maintenance and refurbishment of wear components is a priority. With an array of tips, tip replacement can take the equipment out of service for extended periods.
The tips are close fitting with the bases to provide sufficient support for the tip. Even so, due to the invasiveness of earthen fines and the chaotic nature of a crushing or mining operation, fines commonly get embedded in crevices and openings. The fines consolidate into a concretion with the consistency like concrete and bind mated surfaces. Applied force or a cutting torch is often necessary to separate the components. Hammering and prying of the components may be required which can result in breakage and shrapnel from the target components.